Dying to replicate: the orchestration of the viral life cycle, cell death pathways, and immunity.

Manipulation of cell death pathways has been identified as a common feature of host-microbe interactions. We examine two examples: influenza A as a representative acute infection and cytomegalovirus as an example of chronic infection. From the perspective of viral entry, replication, and transmission, we identify points of interconnection with the host response to infection, namely the induction of host cell death, inflammation, and immunity. Following from this analysis, we argue that the evolution and fine-tuned regulation of death-associated genes may result from constant microbial pressure--past and present--that helped to support and coordinate cell death programs within the host. Interestingly, the delay in host cell death allows time for the virus to replicate while perturbations in cell death allow the host cell to initiate an immune response. This may represent a genetically encoded trade-off ensuring survival of both host and virus, or it may be a part of the complex agenda of infectious microbes.